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Vicinal Diols (vicinal + diol)

Distribution by Scientific Domains

Chemistry	100%

Selected Abstracts

Aminium Hexachloroantimonate Salts as Latent Sources of Antimony Pentachloride in Pinacolic Rearrangement of Vicinal Diols

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 8 2005
Francesco Ciminale, Luigi Lopez
Abstract Rearrangements of various vicinal diols (1a,f) induced by hexachloroantimonate aminium salts A or B were found to occur in a similar manner when antimony pentachloride was used instead of aminium salts. Antimony pentachloride is proposed as the active catalytic species, possibly deriving from the oxidation of the hexachloroantimonate anion SbCl6, by the aminium counterpart. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source]

The fungal metabolite austdiol

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2003
Leonardo Lo Presti
The title compound, (7R,8S)-7,8-dihydroxy-3,7-dimethyl-6-oxo-7,8-dihydro-6H -isochromene-5-carbaldehyde, C12H12O5, is a trans -vicinal diol. Of the two fused rings, which lie approximately in the same plane, the pyran ring is almost perfectly planar, while the cyclohexenone ring adopts a slightly distorted half-chair conformation. The crystal packing is dictated by two strong intermolecular O,H,O interactions, one involving hydroxy and keto groups, the other involving two hydroxy groups. Molecules are linked together through twofold axes, forming zigzag ribbons extended along the a axis. [source]

Aminium Hexachloroantimonate Salts as Latent Sources of Antimony Pentachloride in Pinacolic Rearrangement of Vicinal Diols

Preparation, Characterization and Catalytic Properties of Polyaniline-Supported Metal Complexes

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 12-13 2006
Boyapati
Abstract Polyaniline-supported Sc, In, Pd, Os and Re catalysts were prepared by using a simple protocol and the thus prepared catalysts were well characterized using FTIR, XPS, UV-Vis/DRS, TGA-DTA. All the catalysts were successfully employed in a wide range of organic transformations such as cyanation and allylation of carbonyl compound, Suzuki coupling of aryl halides and boronic acids, and, most importantly, in asymmetric dihydroxylation of olefins to afford optically active vicinal diols. All the catalysts were separated from the reaction mixture by simple filtration and reused with consistent activity for five cycles without noticeable leaching of metal from the support. [source]

Enantioselective separation of chiral vicinal diols in capillary electrophoresis using a mono-6A -aminoethylamino-,-cyclodextrin as a chiral selector

JOURNAL OF SEPARATION SCIENCE, JSS, Issue 1 2009
Peng Liu
Abstract This paper describes an improved access to mono-6A -aminoethylamino-,-CD (,-CDen), a very efficient cationic chiral selector for CZE in the separation of eight chiral aromatic vicinal diols. The ,-CDen concentration has a strong influence on the efficiency of enantioseparation. The effects of the pH and concentration of the BGE, the capillary temperature, and the applied voltage on the resolution and separation selectivity have been studied. Excellent chiral resolution was achieved under the optimal conditions of ,-CDen 10 mM, pH 10, 200 mM borate buffer at 15 kV and 20°C within 20 min. Moreover, the developed method was successfully applied to the determination of the enantiomeric purity of the catalytic asymmetric dihydroxylation (AD) reaction products. [source]

Enantiospecific Syntheses of Copper Cubanes, Double-Stranded Copper/Palladium Helicates, and a (Dilithium),Dinickel Coronate from Enantiomerically Pure Bis-1,3-diketones,Solid-State Self-Organization Towards Wirelike Copper/Palladium Strands,

CHEMISTRY - A EUROPEAN JOURNAL, Issue 5 2008

Abstract Enantiomerically pure, vicinal diols 1 afforded in a two-step synthesis (etherification and subsequent Claisen condensation) chiral bis-1,3-diketones H2L(S,S) (3,a,c) with different substitution patterns. Reaction of these C2 -symmetric ligands with various transition-metal acetates in the presence of alkali ions generated distinct polynuclear aggregates 4,8 by diastereoselective self-assembly. Starting from copper(II) acetate monohydrate and depending on the ratio of transition-metal ion to alkali ion to ligand, chiral tetranuclear copper(II) cubanes (C,C,C,C)-[Cu4(L(S,S))2(OMe)4] (4,a,c) or dinuclear copper(II) helicates (P)-[Cu2(L(S,S))2] (5) could be synthesized with square-pyramidal and square-planar coordination geometry at the metal center. In analogy to the last case, with palladium(II) acetate double-stranded helical systems (P)-[Pd2(L(S,S))2] (6,7) were accessible exhibiting a linear self-organization of ligand-isolated palladium filaments in the solid state with short inter- and intramolecular metal distances. Finally, the introduction of hexacoordinate nickel(II) in combination with lithium hydroxide monohydrate and chiral ligand H2L(S,S) (3,a) allowed the isolation of enantiomerically pure dinuclear nickel(II) coronate [(Li,MeOH)2,{(,,,)-Ni2(L(S,S))2(OMe)2}] (8) with two lithium ions in the voids, defined by the oxygen donors in the ligand backbone. The high diastereoselectivity, induced by the chiral ligands, during the self-assembly process in the systems 4,8 could be exemplarily proven by circular dichroism spectroscopy for the synthesized enantiomers of the chiral copper(II) cubane 4,a and palladium(II) helicate 6. [source]

Synthesis of chiral vicinal diols and analysis of them by capillary zone electrophoresis

CHIRALITY, Issue 2 2008
Peng Liu
Abstract This paper describes an improved access to 1,4-bis (9- O -quininyl) phthalazine [(QN)2PHAL], a very useful chiral ligand for catalytic asymmetric dihydroxylation (AD), by using CaH2 as acid-binding reagent in a high yield under mild conditions. The application of (QN)2PHAL to the AD reactions of eight olefins exhibited excellent enantioselectivity and activity with corresponding chiral vicinal diols. Furthermore, a capillary zone electrophoresis method was developed to separate the aforementioned chiral vicinal diols by using of neutral ,-cyclodextrin (,-CD) as chiral selector and borate as running buffer. High resolution was achieved under the optimal conditions of ,-CD 2.2% (w/v), pH 10, 200 mM borate buffer at 15 kV, and 20°C within 15 min. The relative standard deviations of the corrected peak areas and migration time were less than 3.9% and 1.3%, respectively. In addition, the developed method was successfully applied to the determination of the purity and the enantiomeric excesses value (%ee) of the AD reaction products. Chirality, 2008. © 2007 Wiley-Liss, Inc. [source]